1. Field of the Invention
The present invention is directed to an apparatus for consecutively bonding adhesive tapes to end portions of a fabric containing steel cords.
2. Description of the Prior Art
A steel cord fabric utilized as a reinforcing material for a steel radial tire is typically arranged such that a rubber adhesive tape is so bonded to its section (fabric end portion) as to prevent exposure of the steel cord.
For this purpose, there is employed an apparatus disclosed in, e.g., Japanese Patent Publication No. 11344/1977. This type of apparatus will be explained in conjunction with FIGS. 6 through 10.
Turning first to FIG. 6, a rubber tape C passes through a guide plate 9, and is manually bonded to the lower end of a steel cord fabric A. Thereafter, steel cord fabric A is inserted in between a rotary roll 19 and a press roll 20, whereby a half of rubber tape C is bonded to steel cord fabric A. The remaining half (unbonded portion) of rubber tape C is bent in an L-shape at its end with hands. After this process, the subsequent unbonded portion of rubber tape C is further bent in the L-shape bY the end surface of a side press roller 22. Next, rubber tap C bent in the L-shape is forced, as illustrated in detail in FIGS. 8 to 10, to sequentially pass through grooved rollers 36, 37 and 38, whereby the tape is folded to seize the end portions of steel cord fabric A in a U-shape. Thereafter, rubber tape C is lightly press-fitted onto the upper surface of steel cord fabric A.
Subsequently, rubber tape C is completely press-fitted while passing through between rotary rolls 49 to 51 and press rolls 52 to 54, and is then wound on a winding shaft 60.
A fold bonding mechanism for adhesive rubber sheet C in the prior art apparatus will then be discussed in greater detail with reference to FIGS. 8 to 10.
FIG. 8 illustrates the section orthogonal to the direction in which fabric A moves forward, passing through the center of grooved rollers 37.
FIGS. 9 and 10 are sectional views depicting grooved rollers 36 and 38 disposed in front and in rear of grooved rollers 37.
Each pair of grooved rollers 36, 37 and 38 are rotatably mounted through bearings on shafts 39 embedded erectly into a pair of support boards 40. Support boards 40 are fixed to one ends of a pair of upper and lower guide pins 41 and 42, while the other ends thereof are slidably supported on a sliding member 43.
Each support board 40 is invariably biased from inside by means of a coil spring 44 provided between sliding member 43 and the board itself, thereby imparting a depressing force on steel cord fabric A to grooved rollers 36 through 38.
The grooved rollers pressed on fabric A is freely rotated by frictional forces after fabric A has been carried. The grooves of rollers 36 to 38 are sequentially narrowed in their widths in the feeding direction of fabric A. The groove width of roller 38 disposed last is substantially equal to a thickness of cord fabric A.
Rubber tape C bonded to both ends of fabric A passes sequentially through grooved rollers 36, 37 and 38. Meanwhile, rubber tape C is folded at the ends of fabric A and is then press-fitted.
There arise, however, the following drawbacks inherent in the prior art. (1) After bonding adhesive rubber tape C to steel cord fabric A, fabric A in turn passes through between a pair of rollers 19 and 20. In the meantime, it is required that the end of adhesive rubber tape C be manually bent in the L-shape. Consequently, the folding process of rubber tape C can not completely be automated. (2) In order to fold and press-fit adhesive rubber tape C at both ends of steel cord fabric A, grooved rollers 36, 37 and 38 are pressed down on the end portions of fabric A, and the resultant frictional forces cause grooved rollers 36 through 38 to freely rotate. If a velocity at which steel cord fabric A is carried increases to enhance the productive capability, however, rotational resistances of grooved rollers 36 through 38 augment. As a result, slippage takes place between fabric A and grooved rollers 36 to 38. This in turn causes a difference between the velocities and creases on rubber tape C. Besides, the air permeates in between rubber tape C and steel cord fabric A. These drawbacks are combined to deteriorate the quality of product.